Reverse Osmosis

Practical

Excess Water Catchment

Catch it in a tank and use it to flush toilets. It adds up! Efficient RO system loses 2 or 3 gals instead of 4 for every one you get to use.
Mounted correctly the discharge can flow back to toilets and or a supply tank that they use. Tiny bilge demand float calls for this water to refill toilet tank pumped by tiny dc submersible pump in that reserve tank.